To instrument display boards (dials) arranged on the front surface sides (upper surface sides) of instruments, various characters, numerals, figures, etc. have been conventionally given.
Particularly to time keeping instrument display boards (dials) arranged on the front surface sides (upper surface sides) of time keeping instruments, plural characters, numerals, figures, etc. have been given. Also in time keeping instruments with solar cells (solar batteries), plural characters, numerals, figures, etc. are given to their display boards (dials), similarly to the above, and by combining them, enhancement of visibility and design properties, presentation of a high-class feeling, and the like are carried out.
In the case of such a time keeping instrument dial 100, for example, a method in which a sub-dial 104 is formed in one disc plate 102 by cutting as shown in FIG. 13 has been adopted as a prior art of a patent document 1.
In such a time keeping instrument dial 100, the sub-dial 104 is more depressed than other portions of the time keeping instrument dial 100, so that a stereoscopic feeling is presented by a difference in level between the sub-dial 104 and other portions of the time keeping instrument dial 100.
In the above method, however, there are problems such as restriction of a shape of the sub-dial 104 attributable to the cutting work and a large number of working steps. Moreover, there resides another problem that the time keeping instrument dial 100 must have a certain thickness.
On this account, in the case of a time keeping instrument dial 200 of the patent document 1 shown in FIG. 14, a method in which a lower plate 206 to constitute a sub-dial 204 and an upper plate 202 to constitute a dial base are manufactured in separate steps and they are superposed one upon another has been carried out.
According to such a method, the lower plate 206 to constitute the sub-dial 204 and the upper plate 202 to constitute the dial base are different members, so that a stereoscopic feeling can be presented, and besides, design properties can be enhanced by making the colors of the lower plate 206 and the upper plate 202 different from each other.
The display boards for time keeping instruments with solar cells and the display boards for time keeping instruments with backlight require light transmitting properties, and therefore, time keeping instrument display boards made from resin materials have been employed.
Also in the case of the display boards for time keeping instruments with solar cells and the display boards for time keeping instruments with backlight, which are made from resin materials, two different plates made from resin materials are bonded with an adhesive to form the time keeping instrument display boards, similarly to the time keeping instrument dial 200 shown in FIG. 14, and thereby a stereoscopic feeling can be presented and design properties can be enhanced.
Patent document 1: Japanese Utility Model Laid-Open Publication No. 94664/1974